The invention relates to a punch capable of punching holes in sheet stock of various materials.
Many different types of manual punches are known to the art. However, there exists a continuing need for manual punches which are capable of exerting great force and are lightweight and simple in construction.
It is an object of this invention to provide such a punch.
A punch tool according to one embodiment of the invention comprises just three main components, a frame, a lever arm, and a plunger.
The frame defines a tool head with a handle extending therefrom. The tool head has a front face and a back face, an upper end and a lower end, a first lateral side and a second lateral side. The tool head defines a lower jaw and an upper jaw. The upper jaw is spaced apart from the lower jaw to define a first slot opening into the tool head from the first lateral side between the upper jaw and the lower jaw. The stock to be punched can be received and positioned by the slot.
The lower jaw defines a first vertical borehole which extends alongside the first lateral side of the tool head. The first vertical borehole has a longitudinal axis and opens toward the upper jaw.
The upper jaw defines a second vertical borehole which extends alongside the first lateral side. The second vertical borehole has a longitudinal axis and opens toward the lower jaw. The second vertical borehole is in alignment with the first vertical borehole.
The tool head further defines a second slot which is vertically elongated and forms a passage from the first vertical borehole to the second lateral side of the tool head. A first transverse aperture in the tool head forms a passage extending from the front face of the tool head to the second slot. A second transverse aperture in the tool head forms a passage extending from the back face of the tool head to the second slot. The second transverse aperture is in alignment with the first transverse aperture.
The handle extends from the lower end of the tool head.
A plunger having a first end and a second end is slidably mounted in the first vertical borehole. The plunger has a downwardly facing cam face between its first end and its second end.
A lever arm is positioned in the second slot and actuates the plunger. The lever arm has a cam end, a cam end portion extending from the cam end, a handle end, a handle end portion extending from the handle end, and a pivot portion which connects the cam end portion and the handle portion. A transverse aperture in the pivot portion is provided for receiving a pivot pin.
The lever arm is mounted to the tool head by a pivot pin which extends through the transverse aperture in the lever arm, the first transverse aperture in the tool head, and the second transverse aperture in the tool head. The pivot pin pivotally mounts the lever arm to the tool head with the cam end portion of the lever arm being positioned in the second slot so that the cam end of the lever arm cammingly contacts the downwardly facing cam face of the plunger.
By urging the lever arm toward the handle, the plunger is urged upwardly toward the upper jaw to punch a hole in stock which is positioned in the first slot.